Chapter 8, Problem 27E

(a)

To determine

To explain do you think a linear model is appropriate here.

Answer to Problem 27E

Yes, the linear model is appropriate.

Explanation of Solution

In this question, the researcher wants to find out is the nicotine content of a cigarette related to the “tars”. Thus, a collection of data in milligrams on $29$ cigarettes produced the scatterplot, residual plot and the regression analysis shown in the question. Thus, we think that the linear model is probably appropriate because the residual show some initially low points but there is no clear curvature.

(b)

To determine

To explain the meaning of $R^2$ in this context.

Explanation of Solution

In this question, the researcher wants to find out is the nicotine content of a cigarette related to the “tars”. Thus, a collection of data in milligrams on $29$ cigarettes produced the scatterplot, residual plot and the regression analysis shown in the question. Thus, the meaning of $R^2$ in this context is that the linear model on tar content accounts for $92.4\%$ of the variability in Nicotine.